Refrigeration system



March 21, 1933.

L. U, LARKIN REFRIGERATION SYSTEM Filed Oct. 9, 1930 MA Pg LESTER U. LARKIN, OF

Patented naar. 21, 1933 PATENT OFFICE' ATLANTA, GEORGIAI ASSIGNOR TO LARKIN REFRIGERATING CORPORATION, OF ATLANTA, GEORGIA, A CORPORATION OF GEORGIA REIRIGERATION SYSTEM l Application filed ctober 9, 1930. Serial No. 487,542.

This invention relates to refrigeration sys-I tems of the dry coil type and has for its object the revision of close automatic. control of the a mission of refrigerant to the coil, so that at no time shall the refrigerant be admitted to the coil at a rate faster than it can be evaporated, thus ensuring 100% dryness Within the` coil under all conditions.

Since the evaporative capacity of the coil is dependent upon the rate of heat absorptiom by the refrigerant within the coil, from the refrigerated chamber, pends/ upon the initial low temperature of the refrigerant, as Well as the temperature lof the atmosphere in the refrigerated chamber, it is obvious that since the temperature within the refrigerated chamberitself varies in different locations and from time to time, that no close thermostatic control can be exercised that does not include all of these factors, and that in particular it is not possible to obtain close control by means responsive to the temperature variations in the re.- frigerated chamber. f

However, the temperature variations on the low or eilluent side of the refrigeration 4systemare a direct function of the rate of heat absor tion into the coil, and variations in the sai ratejof heat absorption quickly show up in the etiluent refrigerant. Consequently, a thermostat inserted in the low or effluent conduit leading from the c'oil, or in a portion of the coil itself on the low side, is protected from and therefore, unmodified by direct extraneous finiiuences such as the air temperature in the refrigerated chamber, affords a means for quickly adjusting the supply of refrigerant to the demand.

Another object of the invention resides in the specific means for conveniently mounting the temperature responsive element of the thermostat within the refrigerant pasv sage on the low side.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

In the drawing in which the same characters of reference have been` employed throughout the several figures to designate the several parts: v

which rate in turn de-` lthroughout without ,ant in liquid state.

Figure 1 is aview in elevation showing a fragment of the evaporator coil in a dry coil refrigeration system including the control valve and the thermostatic unit included in the present invention;

Fi ure 2 is a longitudinal section through the lnal portion of the coil pipe showing the fitting, by means of which the thermostatic element may be intercalated in the low side of the system;

Figure 3 is a longitudinal section showing the same type of fitting, but arran ed so that the thermostatic element is in the e uent conduit beyond the coil;

Figure 4 is a perspective View showing a portion of the' thermostatic element and the s lit plug by lmeans of which it is secured in t,e fitting; and

Figure 5 is a perspectiveview of the halves l of the rsplit plug.

`Referring now in detail to the several figu'ies, the numeral 1 represents in eneral the coil of a refrigeration system of t e dry coil type, suchas 1s described and claimed in my copending application, Serial No. 422,364, filed January 21, 1930. Refrigerant in liquefied form is supplied from a condenser, not

shown, by way of the conduit 2 to the control valve 3. Said valve marks the head of the column of liquid refrigerant in the system, and refrigerant is permltted to escape by way of the conduit 4 into the purpose ofthe invention to so control the esca e of the'refrigerant that it will be supe plie only 1n proportion to the expansion capacity of the -coil so that' it shall be evaporated into a, gas by the time it enters said coil to ensure that the coil shall be dry containing any refrigertrol of the valve 3, which control is accomplished by means of a thermostatic element including a hollow bulb 5 and a diaphragm chamber connected by a tube 7 the common chamber thus formed containing aI liquid such for instance, phragm wall of the which is not shown, also not shown.

The evaporative capacity of the coil 1 volatile as ether.A The diadiaphragm chamber 6, controls a valve stem..

This implies a close con coil 1, -it being the v a Y valve 3.

varies accordin to the rate of heat exchange at an moment etween the walls of said coil and t e atmosphere in the refrigerated chamber. This rate of heat exchange in turn, varies with changes in temperature of the at- -mosphere in the refrigerated chamber, and it is alsodetermined by the inition temperature of the refrigerant as well. There is only one element in afrefrigeration system whic responds directly and .quickly to allof these factors, namely the refrigerant in the final portion of the coil conduit or in theadjacelt portion of the eluent conduit leading from coil is only sluggishliy;

' ant, unmodi 4ture variations, 1s capable of lmpartlng an ture of the effluent refrigerant inthe finalv end of the coil or in the adjacent conduit lead`- ing back to the compressor is at an immediate index of the evaporative capacity of the coil, athermostatic element placed within the conduit at this region so as to be affected solely by the tem erature of the effluent refrigeriied by any extraneous temperaexact, immediate and close control to the With this object in view, I' have devised means for the convenient insertion of the bulb 5 in the final end of the coil 1, or selectively, in the adjacent end ofthe .conduit leading from lsaid coil to thelow side of the comv presser. j This means comprises a pige fitting 8, generally in theform of aT avin a^ through bore 9 and a branch nipple 10. ne end of the fitting is counter-bored as indicated at 11, to form a shoulder 12 and the tube 7 of the thermostatic element is provided with` a plug or collar 13 adapted to seat in said counter-bore against the shoulder 12 and to be suitably sealed therein,'-as for instance by sweating with solder. Since the 'thermostatic element including the diatube 7 Consequently, the

phragm chamber, bulb and the' connecting tube comes as an assembled unit with the the volatile liquid enclosed, it is obvious that heat cannot safely be applied either to the bulb or diaphragm chamber on account of risk of bursting the thermostatic element. plug 13 is preferably formed in halves 14 and 15 as indicated in Figure 5, which halves are fitted about the at some point intermediate the diaphragm chamber and bulb, and the halves Aare then sweated or otherwise secured to said tube in Huid-tight relation. I The bulb toa thermostatic element responsive The assembled fitting and thermostatic element thus forms a unit Awhich can be positioned either as shown in Figure 2 with the bulb inserted in the final end of the coil, or it can be positioned as shownI in Figure 3 with the bulb in the eduction pipe. In either instance, the bulb 5 is preferably spaced from the walls of the surrounding conduit so as to be' altogether enveloped by ltheA ellluent refrigerant. The'fact that the tube 7 is bendable makes it possible readily to adjust the 5 so as to place it in the correct position.

The thermostatic .element including the diaphragm chamber, bulb. and connecting tube, with the assembled plug or collar may be sold as an article of manufacture, or it may be supplied in combination with Athe fitting. While the plug 13 is designed eventually to be soldered or sweated into the fitting so as to prevent being blown out by pressure in the system, yet it may be supplied to'the purchaser, unsecured in the fitting with the design that thel purchaser shall solder itin himself.

It is obvious that the invention should not be limited in scope to the. specific form of pipe fitting herein shown or to specific cony struction of thermostatic element and consequently, it is to be understood that variations in the construction of either of thesel features is within the purview of the protection afforded bythe appended claim.

Wha-tIclaimis: In combination, pipe fitting adapted to be intercalated in the conduit -on theA low side of arefrigeration system for the purpose of introducing a thermostat directly into the stream of eluent refrigerant in said system, comprising a Tv having a. l throughbore and a branch nipple, one end of said through-bore being counter-bored, and a thermostatic element comprising a bulb and a tube' connected thereto', said tube passing' axially within s aid through-boreand means secured to said tube and adapted to be secured in sealing relation in the counter-bored end of said T.

In testimony whereof I affix my signature.

LESTER U..` LARKIN. 

